Antibody complex stops rejection

Scientists using mice have carried out tissue transplants without the need for life-long anti-rejection medication.

After a transplant, immunosuppressants need to be administered to prevent the immune system from attacking and rejecting the new tissue. However, these medicines reduce the patients’ ability to resist infection, and increase the risk of cancer and high blood pressure.

So scientists developed a new antibody complex which alters the immune system without the need for immunosuppressants. This complex only needs to be administered in the short term, before the transplant. It works by stimulating immune cells known as T regulatory cells, which subdue the body's immune system.

The complex was administered to mice for three consecutive days to suppress their immune systems, before transplant of pancreatic cells. After the transplant, the numbers of T regulatory cells dropped, returning to normal in about two weeks. By this time four fifths of the mice had accepted the transplanted tissue. After 300 days there were no signs of rejection. Transplants are considered accepted if they haven’t been rejected after 100 days.While cautious, the team are encouraged by the results.

They will try transplanting other organs in mice before looking to see if the technique will work in larger mammals.